Since the upcoming version of Space Engine will feature lakes and seas of liquids other than water, it brings to mind the sorts of precipitation these planets and moons would have. One question it raises for me is what snowflakes of carbon dioxide, methane, or some other volatile look like? Snowflakes on Earth owe their usual six axes of symmetry to a hexagonal structure of water ice. Would we get a similar effect, just with different symmetry?

The shape of all snowflakes depends on the temperature and supersaturation of the air mass in which they form. Under Mars atmospheric pressure, carbon dioxide ice forms at 140°K, or -130°C or -200°F. Water on Mars will boil at 0°C until it freezes.

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Carbon dioxide ice crystallizes with cubic symmetry, this means that it can form cubes, octahedrons, or cuboctahedrons, i.e. cubes with the corners cut off. Under Martian conditions carbon dioxide ice forms cuboctahedrons, just like iron pyrite crystals.

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Extrapolating to cold, low water vapor densities found on Mars we expect to find water ice snowflakes shaped like hexagonal plates and prisms. These shapes will produce halos around the sun with a radius of 22.5 degrees. The angle of ice crystal halos around the Sun when seen on Mars made by carbon dioxide ice cuboctahedrons, form at 28 degrees from the sun.

The shape of all snowflakes depends on the temperature and supersaturation of the air mass in which they form. Under Mars atmospheric pressure, carbon dioxide ice forms at 140°K, or -130°C or -200°F. Water on Mars will boil at 0°C until it freezes.snowflakegraph600.jpegCarbon dioxide ice crystallizes with cubic symmetry, this means that it can form cubes, octahedrons, or cuboctahedrons, i.e. cubes with the corners cut off. Under Martian conditions carbon dioxide ice forms cuboctahedrons, just like iron pyrite crystals.cuboctahedronrh400.jpegExtrapolating to cold, low water vapor densities found on Mars we expect to find water ice snowflakes shaped like hexagonal plates and prisms. These shapes will produce halos around the sun with a radius of 22.5 degrees. The angle of ice crystal halos around the Sun when seen on Mars made by carbon dioxide ice cuboctahedrons, form at 28 degrees from the sun.

Martian Snowflakesmarssnowflakes2600.jpeg

Very interesting

The universe is not required to be in perfect harmony with human ambition.